Flow control device



Aug- 30, 1950 c. H. PEKlNs 2,950,733

FLOW CONTROL DEVICE Filed Oct. 25, 1957 3 Sheets-Sheet 1 ly Z INVENTOR.

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Aug. 30, 1960 Filed OCT.. 25, 1957 C. H. PERKINS FLOW CONTROL DEVICE 3Sheets-Sheet 2 Aug. 30, 1960 c. H. PERKINS 2,950,733

FLOW CONTROL vDEVICE Filed oct. 25, 1957 3 sheets-sheet 5 MTM rates'eten/t:

a assent atenteci Aug. 3), i950 FLOW CONTROL DEVICE Charles H. Perkins,Fountain City, Tenn., assignor to Robertshaw-Fuiton Controls Company,Richmond, Va., a corporation of Delaware Filed Oct. 25, 1957, Ser. No.692,328

13 Claims. (Cl. 137-495) This invention relates generally to devices forcontrolling the ow of liuid through a conduit or the like and moreparticularly to valves for maintaining a constant flow of fluid toconduits irrespective of changes in fluid pressure iu the conduit.

It is well known that a constant flow will be maintained through anorifice of fixed size when the pressure drop across the orifice isconstant. Prior devices of this general type have utilized mechanicalmeans for maintaining a constant flow through an orifice of fixed sizeby `adjusting the pressure on the discharge side of the orifice tocompensate for pressure changes in the supply side of the orifice tomaintain a constant pressure differential therebetween.

in certain of these devices, a pressure responsive means, such as acorrugated, expansible and contractible metallic vessel, is subjected topressures and actuates a valve member on the discharge or supply side ofthe orifice. An increase in pressure on the supply side of the orificeactuates the pressure responsive means to throttle down its associatedvalve to increase the pressure on the discharge side of the orice tomaintain a constant pressure drop across the orifice. The reverse ofthis action occurs when the pressure on the supply side of lthe orificedecreases and the pressure on the discharge side is decreasedproportionately to maintain a constant pressure drop.

In these prior art devices, it has been necessary to provide someconnecting means between the valve member and the pressure responsivemeans so that the valve member will move in response to movement of thepressure responsive means. When this connecting means takes the form ofa valve stem which requires some sort of bearing means, there will be atendency to reduce the accuracy of the flow control as a result of thefriction between the valve stem and the bearing means.

It is an object of the invention to utilize the pressure responsivemeans of a constant iiow valve of the aboveindicated character as avalve member for controlling the pressure drop across an orifice meansthereby eliminating the need for a connecting means between a separatevalve member and pressure responsive means.

vAnother object of the invention is to utilize a combined pressureresponsive means and valve member which is essentially friction-free inits operation in -a valve of the above-indicated character.

Another object of the invention is to maintain a constant pressure dropacross the orifice of a constant flow valve by controlling the effectiveflow area of the metering ports on the discharge side ofthe orifice.

Another object of the invention is to make the unbalanced force acrossthe metering ports of ja constant iiow valve as small as necessary foraccurate tiow control.

In one preferred embodiment of the invention, the flexible diaphragm ispositioned between two casings to define a supply chamber and a meteringchamber. The

iiexible diaphragm contains an orifice of fixed size and is supportedfor movement in response to pressure variations on either the supply orthe discharge side of the orifice. Metering portsare provided incommunication with the metering chamber. The flexible diaphragm iscooperable with the metering ports to control the effective flow areathereof so that a constant pressure drop across the orifice will bemaintained.

The yabove and other objects and features of the invention will appearmore fully hereinafter from a consideration of the following descriptiontaken in connection with the accompanying drawings wherein fourembodiments of the invention are illustrated by way of example.

In the drawings:

Fig. l is a cross-sectional view of a preferred embodiment of theinvention;

iFig. 2 is -a cross-sectional View o-f a second embodiment of theinvention;

.Fig 3 is a cross-sectional view of a third embodiment of the invention;

Fig. 4 is a cross-sectional view of a fourth embodiment of theinvention;

iFig. 5 is a fragmentary, cross-sectional View of a modified detail ofthe invention; and

Fig. 6 is a fragment-ary, cross-sectional view'of another modifieddetail of the invention.

In all of the figures, corresponding parts are designated withcorresponding reference numerals.

Referring now more particularly to Fig. l, the flow control deviceillustrated therein includes a cup-shaped inlet casing 12 having acylindrical portion 11 of reduced diameter extending from the bottomwall thereof to form an inlet passage 18 land an outwardly-extending,annular hanged portion 13 at the open end thereof. A metering cylinder14 having one open end and an outwardly-eX- tending, annular flangedportion 42 at its open end is provided. By juxtaposing the flangedportions 13 and 42, the inlet casing 12 and metering cylinder 14 definea flow control chamber 25 therebetween. Bolts 24 pass through thelianged portions 13 and 42 and are threadedly mounted therein to securethe inlet casing 12 and metering cylinder 14 together. Metering cylinder14 contains a plurality of radially spaced metering ports 20 in the sidewall thereof.

A cup-shaped outlet casing 15 is secured at its open end to the flangedportion 42, as by welding, to enclose metering cylinder 14 and definetherewith an annular outlet chamber 44 in communication with meteringports 20. Outlet casing 16 has a cylindrical portion 21 of reduceddiameter extending from the bottom wall thereof to form an outletpassage 22. Outlet passage 22 is in axial alignment with inlet passage1S.

A flexible diaphragm 26 having -an outer diameter equal to that of angedportions 13 and 42 is supported at its outer diameter between iiangedportions 13 and 42 and at its inner diameter between support plate 34and an annular flange 35 of a cup-shaped orifice plate 36. Flexiblediaphragm 26 has one annular convolution 23 and, along with orificeplate 36, divides the iow chamber 25 into two chambers by defining asupply chamber 3G' with inlet casing 12 and a metering chamber 32 inmetering casing 14.

Orifice plate 36 is secured tightly within a central opening 37 insupport plate 34 and contains an orifice 40 in the bottom wall thereof.Support plate 34 is cupshaped and is mounted on load spring 38 with theopen end of the plate facing the bottom wall of metering cylinder 14.The load spring 33 is positioned between the bottom wall of meteringcylinder 14 and the bottom wall of support plate 34. The bottom wall ofmetering cylinder 14 has a raised portion 39 for retaining the spring 38in its operating position.

In the operation of Athe embodiment shown in Fig. 1,

fluid enters the valve throughpassage 18 of inlet 'casing 12 and passesinto supply chamber 30. Fluid willA then pass from supply chamber 30 tometering chamber 32 through orice 40, through metering ports 20 tooutlet chamber 44, and out of the valve through outlet passage 22. Theuid undergoes a pressure drop from P1 to P2 as it passes through orice40. This pressure diierential produces a force which causes the ilexiblediaphragm 26 and support plate 34 to compress spring 38. Spring 38develops a load, in accordance with its spring rate, equal in magnitudebut opposite in direction to such compressing force and 'in response toa predetermined pressure' drop.P1 to P2, spring 38 Will hold theflexible diaphragm 26 and support plate 34 in an equilibrium position asshown in Fig. l. Y When the pressure drop (P1 to P2) begins to exceedthis predetermined value, the ilexible diaphragm 26 and support plate 34move in a direction tending to further compress the spring 3S. Theexible diaphragm 26 will tend to roll down the inside wall'of meteringcylinder 14 across the metering ports 20 thereby restricting the ow ofuid therethrough. This restriction of llow will decrease the value ofthe pressure drop until it reaches the initial predetermined value.Therefore, the constant iiow through orifice 40 will exist for allpressure drops across the valve that are in excess of the predeterminedpressure drop.

In'the embodiment of the invention shownin Fig. 2, a stem member 48 isiixed at one end thereof to the center of support plate 234. An orificecylinder 236 having an orice 240 is mounted on support plate 234. Theother end of stem member 48 extends through opening 46 in inlet casing212 toward a point externally of the valve. Hence, the flow of uidthrough the Valve may be externally controlled by means of stem 4S. Inall respects, the construction and operation of the" Fig. 2 embodimentis similar to the Fig. l embodiment hereinbefore described.

The embodiment shown in Fig. 3 is substantially the same as that shownin Fig. 1, the only difference being that an adjustable orifice cylinder336 is used instead of a iixed oritice cylinder.V Oriiice cylinder 336defines an orifice chamber 50 and includes ra pair of inlet ports 52, 54providing a ow passage from supply chamber 330 to orifice chamber 50.Orice cylinder 336 also has an orice 340 providing a flow passage for aow of fluid from orice chamber 50 to metering chamber 32. A pointed stemmember 56 is threadedly mounted in orifice cylinder 336 for movementinto oriiice 340 to vary the eiective iow area thereof. By using theadjustable orifice of the Fig. 3 embodiment, a constant ow valve thatmay be adjusted for a variety of flow rates will result.

Fig. 4 illustrates another embodiment of the invention in which anadjustable orifice is used. In the device there shown, two supplycompartments 60, 62 are provided. Compartment 60 is defined by inletcasing 64, which contains an inlet passage 66 for a flow of fluid intothe valve, and compartment 62 is deiined by inlet casing 68.Compartments 60, 62 are interconnected by a `conduit 70. A meteringcasing 414 is secured to inlet casings 64, 68 by suitable means, such asbolts 24 in the case of casing 68 or welding in the case of casing 64.AFlexible diaphragm 26Yis disposed between inlet casing 68 and meteringcasing4 414 and is supported at the center thereof by support plate 34,spring 38 and Vcylinder 72 in a manner similar to that of the Fig. 1device. It is toV be noted that cylinder Y72 has no orifice therein;however, metering casing 414 is provided with an orice 74 defining aflow passage between supply compartment 60 and metering chamber V432.Metering casing 41,4 also contains radially spaced metering ports Y20therein. A11

outlet casing 416 s secured to a ilanged portion 442 in metering chamber414, as by Welding, to form an outlet chamber 444 therewith. Outletcasing 416 contains an outlet passage 422 for the ow of uid from thevalve.`

A pointed stem member 76 having a handle 78 is threadedly mounted ininlet casing 64 for movement into orice 74 to vary the eiective ow areathereof. Hence, the Fig. 4 embodiment Yillustrates a constant tlow valvesimilar to the valve of Fig. l in its operation and operable within avariety of ow rates. Y

Fig. 5 shows a metering cylinder'14 having helically spaced ports 80therein and Fig. 6 Vshows a metering cylinder 14 with helically spacedslots 82 therein. By spacing the metering ports of a metering cylinder14 in a helical manner, the amount of opening of these ports per unitmovement of the annular convolution 28 of the flexible diaphragm 26 maybe varied by changing either the angle of'the helix or the spacing oftheY ports. Since' there is a pressure drop P2 to P3 across the portionof the annular convolution 28 of the flexible diaphragm 26, when thisportion of the diaphragm isrcovering or uncovering vthe metering ports,an unbalanced force is set up which resists the uncovering of the portsand assists the covering of such ports. This unbalanced force may bemade as small as necessary for accurate control by the spacing of theports along a helix. It will be understood that either helical ports 80or helical slots 82 may be used in any of the embodiments shown in Figs.1 to 4 in place of the radially spaced ports 28.

In the application of this invention, the predetermined pressure drop P1to P2 may be made very low (approximately 5 p.s.i.) and the valve partsmay be made structurally strong enough so that the valve may have auseful operating pressure range of approximately 5 to 150 An advantageof this invention is that the device is essentially friction-free asthel result of the rolling action of the flexible diaphragm 26 therebycontributing to the accuracy of the dow control.

Another advantage of this invention is that the constant flow valve maybe used on either well-strained liquids or liquids having suspendedparticles of dirt or foreign matter therein. The only restriction on thesize of the particles is that it must be small enough to pass throughthe metering ports 2t).V It will be apparent that since there are noclose fitting or sliding parts and since the only relative movement ofthe parts is the rolling action of the iiexible diaphragm 26 against themetering cylinder 14, it is very unlikely that dirt or other foreignmaterial will cause this constant tiow valve to stick or otherwisebecome inoperative.

It is to be understood that although several embodiments of thisinvention have been shown and described, the invention can be variouslyembodied and changes may be made in the construction and arrangement ofparts without departingfrom the scope of the invention as defined by theappended claims.

I claim:

1. In a low control device, the combination comprising a rst casinghaving an inlet passagefor Va ow of iiuid, a second casing having portmeans for la ow of fluid therethrough, said rst and second casings beingjuxtapositioned to deiine a ow control chamber therebetween, meanscommunicating with Vsaid port means for receiving the ow of fluidtherefrom and having an outlet passage for the ow of fluid from saidflow controldevice, flow control means within said flow control chamberincluding a valve means mounted for movement between ow controllingpositions .to` restrict the iiow of fluid through said port means andVrestricted orifice means dening a passage for the ow of iluid from saidinlet passage to said port means, said valve means dividing said flowcontrol chamber into a rst chamber communicating with -said inletpassage and a second` chamber commuuicating with said port means, meansconnected to said valve means for controlling the :dow controllingposition thereof from a point externally of said ow control chamber,said valve means comprising a flexible diaphragm cooperable with saidsecond casing to increase the effective flow control area of said portmeans in response to the iiuid pressure differential between said rstand second chambers, and yieldable means operably disposed in saidsecond chamber and biasing said liexible diaphragm out of cooperationwith said second casing to decrease the effective iiow control area ofsaid port means.

2. A ow control device as claimed in claim 1 wherein said means forcontrolling the flow controlling position of said valve means from apoint externally of said ow control chamber comprises a stem memberhaving one end thereof connected to said valve means and the other endthereof projecting through said iirst casing to a point externallf,I ofsaid first casing.

3. In a iiow control device, the combination comprising a first casinghaving an inlet passage for a ow of uid, a second casing having portmeans for a flow of uid therethrough, said rst and second casings beingjuxtapositioned to define a flow control chamber therebetween, meanscommunicating with said port means for receiving a flow of uid therefromand having an outlet passage for a iiow of iiuid, ow control meanswithin said iiow control chamber, a supply compartment in said owcontrol chamber defined by said first casing and said flow controlmeans, a metering compartment in said iiow control chamber defined bysaid second casing and said ow control means, said flow control meansincluding restricted orifice means defining a flow passage for the ow ofuid from said supply compartment to said metering compartment and avalve means movable between ow controlling positions to restrict theiiow of uid through said port means, said valve means comprising aflexible diaphragm member movable into engagement with said secondcasing in response to the fluid pressure diierential between said supplyand metering compartments to cover said port means, yieldable meansbiasing said exible diaphragm in a direction to uncover said port means,and means cooperable with said orice means for regulating the eectiveiiow area of the flow passage defined thereby, said valve means beingoperable to control the effective flow area of said port means tomaintain a constant pressure drop across said orifice means.

4. A iiow control device as claimed in claim 3 wherein said means forregulating the effective ow area of the ow passage deiined by saidrestricted oriiice means comprises a stern member adjustably mounted formovement into various positions.

5. in a iiow control device, the combination comprising a first chambermeans including a iirst housing having an inlet passage for a ow offluid, a second housing and means interconnecting said rst and secondhousings for a flow of uid therebetween ,a second chamber means havingport means for a How of uid therethrough, said first and second chambermeans being juxtapositioned to define a flow control chambertherebetween, means communicating with said port means for receiving aflow of iluid therefrom and having an outlet passage for a ow of uid,iiow control means within said flow control chamber having restrictedorifice means deiining a passage for a flow of uid and a valve meansmovable between .flow controlling positions to restrict the ow of uidthrough said port means, a first supply compartment in said flow controlchamber defined by said orifice means and said first housing of saidiirst chamber means, a second supply compartment in said flow controlchamber defined by said valve means and said second housing of said rstchamber means, a metering compartment in said flow control chamber denedby said valve means and said orifice means in conjunction with saidsecond chamber means, means cooperable with said orifice means forregulating the eective ow area of the ow passage dened by said orificemeans, said valve means comprising a exible diaphragm operablyengageable with said port means to decrease the elective ow area of saidport means in response to the tiuid pressure differential between saidsecond supply compartment and said metering compartment, and yieldablemeans biasing said flexible diaphragm away from engagement with saidport means to increase the etective iiow area thereof.

6. A flow control device as claimed in claim 5 wherein said means forregulating the effective iiow area of the flow passage defined by saidrestricted orice means comprises a pointed stern adjustably mounted andhaving a portion thereof extending externally of the rst supplycompartment.

7. In a iiow control device, the combination comprising a. casing havingan inlet and an outlet, a wall means in said casing dening a ow controlchamber therein, port means in said wall means defining a ow passagewaybetween said ow control chamber and said outlet, means defining arestricted ow passageway between said inlet and said port means, valvemeans positioned within said iiow control chamber for dividing the sameinto a first chamber in communication with said inlet and a secondchamber in communication with said port means, said valve meanscomprising a flexible diaphragm member movable into engagement with saidwall means in response to the-Huid pressure diierential between said rstand second chambers to cover said port means, and yieldable meansbiasing said eXible diaphragm in a direction to uncover said port means.

8. A device `as claimed in claim 7 wherein said wall means issubstantially cylindrical and said exible diaphragm member has anannular convolution and is positioned for rolling engagement with saidwall means duringr said movement thereof.

9. A device as claimed in claim 8 wherein said yieldable means forbiasing said flexible diaphragm in a direction to uncover said portmeans comprises a coil spring mounted in said second chamber.

10. A iiow control device as claimed in claim 7 wherein said meansdening a restricted flow passageway between said inlet and said portmeans includes an orifice member carried by said ilexible diaphragm.

11. A iiow control device as claimed in claim 8 wherein the port meansof said second casing comprises a plurality of circumferentially spacedports.

12. A flow control device as claimed in claim 8 wherein said port meansof said second casing comprises a plurality of helically spaced ports.

13. A flow control device as claimed in claim 8 wherein said -port meansof said second casing comprises a plurality of helically spaced slots.

References Cited in the tile of this patent UNITED STATES PATENTS611,519 Simmance Sept. 27, 1898 2,069,022 Sisk Jan. 26, 1937 2,219,408Benz et al Oct. 29, 1940 2,615,675 Mellert Oct. 28, 1952 2,736,332Simmons Feb. 29, 1956 2,777,464 Mosely Jan. 15, 1957 FOREIGN PATENTS133,564 Australia July 18, 1949

